Seems to me there used to be a set of flags that allowed increase of polyphony and stream from disk/ram options. But I can't even seems to find them with Google as my friend. It's been over a year since I compiled my own but I missed these optimizations... It used to be right there in the compile docs...

Thats not necessary anymore. You can now adjust the limit for voices and disk streams at runtime. There is however still such configure parameters which now define the default amount of voices and disk streams, but as said, they can be overridden at runtime at any time. But anyway, the parameters are --enable-max-voices=NUMBER and --enable-max-streams=NUMBER